Dicing die-bonding film

ABSTRACT

The invention relates to a dicing die-bonding film having a pressure-sensitive adhesive layer ( 2 ) on a substrate material ( 1 ) and a die-bonding adhesive layer ( 3 ) on the pressure-sensitive adhesive layer ( 2 ), wherein the adhesion of the pressure-sensitive adhesive layer ( 2 ) to the die-bonding adhesive layer ( 3 ), as determined under the conditions of a peel angle of 15° and a peel point moving rate of 2.5 mm/sec. at 23° C., is different between a region ( 2   a ) corresponding to a work attachment region ( 3   a ) and a region ( 2   b ) corresponding to a part or the whole of the other region ( 3   b ), in the die-bonding adhesive layer ( 3 ), and satisfies the following relationship: adhesion of the pressure-sensitive adhesive layer ( 2   a )&lt;adhesion of the pressure-sensitive adhesive layer ( 2   b ), and the adhesion of the pressure-sensitive adhesive layer ( 2   a ) to the die-bonding adhesive layer ( 3 ) is not higher than 2.3 N/25 mm. There is thus provided the dicing die-bonding film that is excellent in balance between retention during dicing of the thin work and releasability of its diced chipped work together with the die-bonding adhesive layer, even if a work is thin.

FIELD OF THE INVENTION

The present invention relates to a dicing die-bonding film. The dicingdie-bonding film is used in dicing a work (semiconductor wafer or thelike) on which an adhesive for fixing a chipped work (semiconductor chipor the like) to an electrode member was stuck before dicing. The presentinvention also relates to a method of fixing a chipped work by using thedicing die-bonding film. Further, the present invention relates to asemiconductor device having a chipped work adhesive-fixed thereon by thefixing method. For example, the dicing die-bonding film of the presentinvention can be applied to various works such as siliconsemiconductors, compound semiconductors, semiconductor packages, glassand ceramics.

BACKGROUND OF THE INVENTION

A semiconductor wafer having a circuit pattern formed thereon issubjected if necessary to backside polishing to regulate the thicknessand then subjected to dicing into a chipped work (dicing step). In thedicing step, the semiconductor wafer is washed generally at suitablefluid pressure (usually about 2 kg/cm²) in order to remove off-cut.Then, the chipped work is fixed via an adhesive onto an adherend such asa lead frame (mounting step) and then subjected to a bonding step. Inthe mounting step, an adhesive has conventionally been applied on thelead frame or the chipped work. In this method, however, the adhesivelayer is hardly uniformly applied, and the application of the adhesiverequires a special device and is time-consuming. Accordingly, a dicingdie-bonding film for retaining a semiconductor wafer via an adhesive inthe dicing step and providing a chip-bonding adhesive layer necessary inthe mounting step has been proposed (see, for example, JP-A 60-57642).

The dicing die-bonding film described in JP-A 60-57642 supra comprisesan adhesive layer arranged releasably on a substrate material. That is,a semiconductor wafer retained by the adhesive layer is subjected todicing, and the substrate material is stretched to release the resultingchipped works together with the adhesive layer therefrom, and eachchipped work is recovered and then fixed via the adhesive layer to anadherend such as a lead frame.

The adhesive layer in this kind of dicing die-bonding film is desired toexhibit good retention of the semiconductor wafer as well as goodreleasability of the chipped work together with the adhesive layer fromthe substrate material after dicing in order to prevent problems such asdicing infeasibility and erroneous dimensions. However, these twofeatures are hardly balanced. Particularly, when the adhesive layerrequires high retention in a system of dicing a semiconductor wafer witha rotating round blade, it is difficult to obtain a dicing die-bondingfilm satisfying these features.

To overcome this problem, a wide variety of modifications have beenproposed (see, for example, JP-A 2-248064). JP-A 2-248064 proposes amethod of facilitating pickup of chipped works, which comprisessandwiching a UV radiation-curing pressure-sensitive adhesive layerbetween a substrate material and an adhesive layer and then curing itwith UV rays after dicing to reduce the adhesion between thepressure-sensitive adhesive layer and the adhesive layer therebyreleasing the layers from each other.

However, there is the case where even by this modification method, goodbalance between retention during dicing and releasability after dicingis hardly attained by the adhesive layer. For example, when a largechipped work of 10 mm×10 mm or more is to be obtained, easy pickup ofthe chipped work is infeasible with a general die bonder because of thelarge area of the work.

To solve this problem, the present applicant applied a dicingdie-bonding film excellent in balance between the retention of a workduring dicing and releasability of its diced chipped work together witha die-bonding adhesive layer (JP-A 2002-299930). Even in the pickup stepusing this dicing die-bonding film, a system of using a general dicingpressure-sensitive film is adopted. That is, the dicing die-bonding filmis stretched to a certain extent, and the dicing die-bonding film belowa chipped work to be picked up is raised or rubbed in a dotted or linearstate to facilitate the release of the chipped work from the dicingdie-bonding film, and the chipped work is picked up by upward vacuumadsorption. The dicing die-bonding film in the application supra canachieve excellent pickup.

In recent years, however, the works (semiconductor elements) arerendered thinner with spread of IC cards etc., and the chipped works areeasily deformed (pliable) upon pickup by the technique described above,and the peel angle of the dicing die-bonding film to the chipped worktends to be reduced. As a result, the peeling strength is increased tohinder pickup.

The mechanism of pickup of thin chipped works is approximately estimatedas follows: That is, when the thin chipped works are to be picked up,the dicing die-bonding film is raised with a raising pin to facilitaterelease, upon which the works are thin and poor in rigidity so that theedge of the works is deformed to make the peel angle between the dicingdie-bonding film and the works lower than in the case of conventionalthick works having rigidity, thus increasing the peeling strength tohinder pickup.

SUMMARY OF THE INVENTION

An object of the present invention is to provide a dicing die-bondingfilm having a pressure-sensitive adhesive layer on a substrate materialand a die-bonding adhesive layer arranged releasably on thepressure-sensitive adhesive layer, which even if the work is thin, isexcellent in balance between the retention of the thin work duringdicing and the releasability of its diced chipped work together with thedie-bonding adhesive layer.

Another object of the present invention is to provide a method of fixinga chipped work by using the dicing die-bonding film. A further object ofthe present invention is to provide a semiconductor device comprising achipped work adhesive-fixed thereon by the fixing method.

As a result of extensive study to solve the problem described above, thepresent inventors found the following dicing die-bonding film, thusarriving at completion of the present invention.

That is, the present invention relates to a dicing die-bonding filmhaving a pressure-sensitive adhesive layer (2) on a substrate material(1) and a die-bonding adhesive layer (3) on the pressure-sensitiveadhesive layer (2),

wherein the adhesion of the pressure-sensitive adhesive layer (2) to thedie-bonding adhesive layer (3), as determined under the conditions of apeel angle of 15° and a peel point moving rate of 2.5 mm/sec. at 23° C.,is different between a region (2 a) corresponding to a work attachmentregion (3 a) and a region (2 b) corresponding to a part or the whole ofthe other region (3 b), in the die-bonding adhesive layer (3), andsatisfies the following relationship: adhesion of the pressure-sensitiveadhesive layer (2 a)<adhesion of the pressure-sensitive adhesive layer(2 b), and the adhesion of the pressure-sensitive adhesive layer (2 a)to the die-bonding adhesive layer (3) is not higher than 2.3 N/25 mm.

The dicing die-bonding film of the present invention has apressure-sensitive adhesive layer (2) on a substrate material (1) and adie-bonding adhesive layer (3) arranged releasably on thepressure-sensitive adhesive layer (2). The pressure-sensitive adhesivelayer (2) is designed such that the adhesions of the regions (2 a and2b) corresponding to the work attachment region (3 a) and the otherregion (3 b) in the die-bonding adhesive layer (3) to the die-bondingadhesive layer (3) satisfy the following relationship: adhesion of thepressure-sensitive adhesive layer (2 a)<adhesion of thepressure-sensitive adhesive layer (2 b). That is, the pressure-sensitiveadhesive layer (2 b) is designed to adhere suitably to the adhesivelayer (3) upon dicing or expansion, thus preventing release of theadhesive layer (3) from the pressure-sensitive adhesive layer (2). Onthe other hand, the pressure-sensitive adhesive layer (2 a) is designedto be easily releasable. Accordingly, there can be obtained a dicingdie-bonding film by which even a large chip having dimensions exceeding10 mm×10 mm can be subjected to dicing without failure, and afterdicing, the resulting chipped work can be easily released and picked up.Thus, the dicing die-bonding film of the present invention attains goodbalance between retention during dicing and releasability during pickup.

Further, the adhesion of the pressure-sensitive adhesive layer (2) tothe die-bonding adhesive layer (3) is as low as 2.3 N/25 mm or less evenat a peel angle as low as 15°. Accordingly, even if the work is thin andeasily deformable to decrease the peel angle during pickup, the chippedwork can be excellently picked up. The adhesion is preferably not higherthan 2.0 N/25 mm, more preferably not higher than 1.8 N/25 mm. Toprevent chip scattering etc., the adhesion is preferably not lower than0.1 N/25 mm, more preferably not lower than 0.3 N/25 mm.

In the dicing die-bonding film, the adhesions of the work attachmentregion (3 a) in the die-bonding adhesive layer (3) to the work and tothe pressure-sensitive adhesive layer (2 a) preferably satisfy thefollowing relationship: adhesion to the work>adhesion to thepressure-sensitive adhesive layer (2 a).

The adhesion of the die-bonding adhesive layer (3) satisfies the aboverelationship between the work and the pressure-sensitive adhesive layer(2 a), so that after dicing the work, the chipped work to which thedie-bonding adhesive layer (3) has been stuck can be easily releasedfrom the pressure-sensitive adhesive layer (2 a).

In the dicing die-bonding film, a part of the region (3 b) other thanthe work attachment region (3 a) can be a dicing ring attachment region(3 b′). In the dicing die-bonding film, the adhesions of the dicing ringattachment region (3 b′) in the die-bonding adhesive layer (3) to thedicing ring and to the pressure-sensitive adhesive layer (2 b′)preferably satisfy the following relationship: adhesion to the dicingring<adhesion to the pressure-sensitive adhesive layer (2 b′).

The adhesion of the die-bonding adhesive layer (3) satisfies the aboverelationship thereby improving the balance between retention duringdicing and releasability during pickup.

Further, the present invention relates to another dicing die-bondingfilm having a pressure-sensitive adhesive layer (2) on a substratematerial (1) and a die-bonding adhesive layer (3) on thepressure-sensitive adhesive layer (2),

wherein the die-bonding adhesive layer (3) is arranged as a workattachment region (3 a) on a part of the pressure-sensitive adhesivelayer (2), and the adhesion of the pressure-sensitive adhesive layer (2)to the die-bonding adhesive layer (3), as determined under theconditions of a peel angle of 15° and a peel point moving rate of 2.5mm/sec. at 23° C., is different between a region (2 a) corresponding tothe work attachment region (3 a) and other region (2 b), in thepressure-sensitive adhesive layer (2), satisfies the followingrelationship: adhesion of the pressure-sensitive adhesive layer (2a)<adhesion of the pressure-sensitive adhesive layer (2 b), and theadhesion of the pressure-sensitive adhesive layer (2 a) to thedie-bonding adhesive layer (3) is not higher than 2.3 N/25 mm.

The another dicing die-bonding film of the present invention has apressure-sensitive adhesive layer (2) on a substrate material (1) and adie-bonding adhesive layer (3) arranged releasably as a work attachmentregion (3 a) on a part of the pressure-sensitive adhesive layer (2). Thepressure-sensitive adhesive layer (2) is designed such that theadhesions of region (2 a) corresponding to the work attachment region (3a) and other region (2 b) satisfy the following relationship: adhesionof the pressure-sensitive adhesive layer (2 a)<adhesion of thepressure-sensitive adhesive layer (2 b). That is, the pressure-sensitiveadhesive layer (2 a) is designed to be easily releasable. On the otherhand, the pressure-sensitive adhesive layer (2 b) can bond a wafer ringand fix it so as not to be releasable upon dicing or expansion.Accordingly, there can be obtained a dicing die-bonding film by whicheven a large chip having dimensions exceeding 10 mm×10 mm can besubjected to dicing without failure, and after dicing, the resultingchipped work can be easily released and picked up. The another dicingdie-bonding film of the present invention attains good balance betweenretention during dicing and releasability during pickup.

Further, the adhesion of the pressure-sensitive adhesive layer (2) tothe die-bonding adhesive layer (3) is as low as 2.3 N/25 mm or less evenat a peel angle as low as 15°. Accordingly, even if the work is thin andeasily deformable to reduce the peel angle during pickup, the chippedwork can be excellently picked up. The adhesion is preferably not higherthan 2.0 N/25 mm, more preferably not higher than 1.8 N/25 mm. Forpreventing chip scattering etc., the adhesion is preferably not lowerthan 0.1 N/25 mm, more preferably not lower than 0.3 N/25 mm.

In the another dicing die-bonding film, the adhesions of the workattachment region (3 a) to the work and to the pressure-sensitiveadhesive layer (2 a) preferably satisfy the following relationship:adhesion to the work>adhesion to the pressure-sensitive adhesive layer(2 a).

The adhesion of the die-bonding adhesive layer (3 a) satisfies the aboverelationship between the work and the adhesive layer (2 a), so thatafter dicing the work, the chipped work to which the die-bondingadhesive layer (3 a) has been stuck can be easily released from thepressure-sensitive adhesive layer (2 a).

In the dicing die-bonding films (1) and (2), the pressure-sensitiveadhesive layer (2) is formed preferably from a radiation-curingpressure-sensitive adhesive, and the pressure-sensitive adhesive layer(2 a) corresponding to the work attachment region (3 a) can be formed byirradiating the radiation-curing pressure-sensitive adhesive withradiations.

The radiation-curing pressure-sensitive adhesive used is preferably anadhesive comprising an acrylic polymer having a glass transitiontemperature of −70° C. or more. Preferably, the radiation-curingpressure-sensitive adhesive preferably comprises an acrylic polymerhaving a weight-average molecular weight of 500,000 or more. Theradiation-curing pressure-sensitive adhesive is preferably the onecontaining 40 wt % or more of a radiation-curing resin containing 6 ormore carbon-carbon double bonds on average in one molecule.

From the viewpoint of reducing the adhesion of the pressure-sensitiveadhesive layer to the die-bonding adhesive, the tensile storage elasticmodulus of the die-bonding adhesive layer (3) at 25° C. is preferably 50MPa or more in the dicing die-bonding films before the die-bondingadhesive layer (3) is stuck to a chipped work etc., then stuck to asemiconductor element and finally fixed (for example by curing in thecase of a thermosetting adhesive). The tensile storage elastic modulusis preferably 70 MPa or more, more preferably 80 MPa or more. From theviewpoint of attachment to the work, the tensile storage elastic modulusis preferably 2500 MPa or less, more preferably 1000 MPa or less, stillmore preferably 500 MPa or less.

The present invention also relates to a method of fixing a chipped work,which comprises the steps consisting of:

-   -   contact-bonding a work onto the die-bonding adhesive layer (3 a)        of the dicing die-bonding film described above,    -   dicing the work into a chipped work,    -   releasing the chipped work together with the die-bonding        adhesive layer (3 a) from the pressure-sensitive adhesive layer        (2 a), and    -   adhesive-fixing the chipped work via the die-bonding adhesive        layer (3 a) onto a semiconductor element.

The method of fixing the chipped work is also preferable in the casewhere the thickness of the work is less than 100 μm. The method can alsobe carried out preferably in the case where the thickness of the work isless than 50 μm.

Further, the present invention relates to a semiconductor devicecomprising a chipped work adhesive-fixed via the die-bonding adhesive (3a) onto a semiconductor element by the above method of fixing a chippedwork to a substrate or a chip.

BRIEF DESCRIPTION OF THE DRAWINGS

Further other objects, features and excellent aspects of the presentinvention will be sufficiently understood by the following description.The advantage of the present invention will be clarified by thefollowing description with reference to the accompanying drawings.

FIG. 1 is one example of a sectional view of the dicing die-bonding film(11) of the present invention.

FIG. 2 is one example of a sectional view of the dicing die-bonding film(12) of the present invention.

FIG. 3 is one example of a sectional view of the dicing die-bonding film(13) of the present invention.

DESCRIPTION OF THE EMBODIMENTS

Hereinafter, the dicing die-bonding film of the present invention isdescribed by reference to the drawings. FIGS. 1 and 2 show one exampleof a sectional view of the dicing die-bonding film (11) of the presentinvention, which has a pressure-sensitive adhesive layer (2) on asubstrate material (1) and a die-bonding adhesive layer (3) on thepressure-sensitive adhesive layer (2).

In FIG. 1, the respective regions (2 a, 2 b) are designed such that ininterface (A) corresponding to the work attachment region (3 a) andinterface (B) corresponding to the other region (3 b), the releasabilityof the pressure-sensitive adhesive layer (2) from the die-bondingadhesive layer (3) satisfies the following relationship: peel strengthof the interface (A)>peel strength of the interface (B). Thepressure-sensitive adhesive layer (2 a) corresponds to the workattachment region (3 a) and the pressure-sensitive adhesive layer (2 b)corresponds to the other region (3 b), in the die-bonding adhesive layer(3).

FIG. 2 shows an example where a part of the region (3 b) corresponds tothe dicing ring attachment region (3 b′). That is, the peel strength ofinterface (B′) between the dicing ring attachment region (3 b′) and itscorresponding pressure-sensitive adhesive layer (2 b′) is designed tosatisfy the following relationship: peel strength of interface (A)>peelstrength of interface (B′). The pressure-sensitive adhesive layer (2) inFIG. 1 is the pressure-sensitive adhesive layer (2 b) except for thepressure-sensitive adhesive layer (2 a), but as shown in FIG. 2, a partof the region other than the pressure-sensitive adhesive layer (2 a) canbe the pressure-sensitive adhesive layer (2 b).

FIG. 3 shows one example of a sectional view of the dicing die-bondingfilm (13) of the present invention, which has a pressure-sensitiveadhesive layer (2) on a substrate material (1) and has a work attachmentregion (3 a) on a part of the pressure-sensitive adhesive layer (2). Therespective regions (2 a, 2 b) are designed such that in thepressure-sensitive adhesive layer (2), the region (2 a) corresponding tothe work attachment region (3 a) and the other region (2 b) are designedto satisfy the following relationship: adhesion of thepressure-sensitive adhesive layer (2 a)<adhesion of thepressure-sensitive adhesive layer (2 b).

The substrate material (1) confers strength on the dicing die-bondingfilm. Examples of the substrate material include polyolefins such aslow-density polyethylene, linear polyethylene, middle-densitypolyethylene, high-density polyethylene, ultra-low-density polyethylene,random copolymerization polypropylene, block copolymerizationpolypropylene, homopolypropylene, polybutene, polymethyl pentene etc.,polyesters such as ethylene/vinyl acetate copolymer, ionomer resin,ethylene/(meth)acrylic acid copolymer, ethylene/(meth)acrylate (random,alternating) copolymer, ethylene/butane copolymer, ethylene/hexenecopolymer, polyurethane, polyethylene terephthalate, polyethylenenaphthalate etc., polycarbonate, polyimide, polyether ether ketone,polyimide, polyether imide, polyamide, every aromatic polyamide,polyphenyl sulfide, aramid (paper), glass, glass cloth, fluorine resin,polyvinyl chloride, polyvinylidene chloride, cellulose resin, siliconeresin, metal (foil), paper etc. The material of the substrate materialincludes polymers such as those crosslinked from the resin describedabove. The exemplary material constituting the substrate material may beused after grafting a functional group, a functional monomer or amodifying monomer onto it if necessary.

When the substrate material is composed of a plastic film, the plasticfilm may be used in a non-stretched form or after subjection ifnecessary to uniaxial or biaxial stretching treatment. According to aresin sheet endowed with thermal shrinkability by stretching treatment,the substrate material can be thermally shrunk after dicing therebyreducing the contact area between the pressure-sensitive adhesive layer(2 a) and the adhesive layer (3 a) to facilitate the recovery of chippedworks.

The method of making a film of the substrate material can be carried outby a conventionally known film-making method. For example, calender filmmaking, casting film making, inflation extrusion, T-die extrusion etc.can be preferably used. The surface of the substrate material can besubjected to ordinary surface treatment, for example chemical orphysical treatment such as chromate treatment, ozone exposure, flameexposure, high-voltage electric shock exposure, ionization radiationtreatment etc. or coating treatment such as a prime coating (forexample, tacky substance described later) in order to increase theadhesiveness, retention etc. of its adjacent layer.

The same or different kinds of substrate material (1) can be suitablyselected and used. The substrate material may be a single layer ormultilayer or may be a blend substrate material having two or more kindsof resins dry-blended therein. The multilayer film can be produced fromthe above resin etc. by a conventional film lamination method such asco-extrusion method, dry lamination method etc. The substrate material(1) can be provided thereon with a evaporated layer of about 30 to 500 Åconsisting of an electroconductive material such as a metal, an alloyand an oxide thereof in order to confer antistatic performance. Thesubstrate material (1) may be a single layer or a multilayer consistingof two or more layers. When the pressure-sensitive adhesive layer (2) isa radiation-curing adhesive layer, the substrate material permittingradiations such as X-ray, UV ray, electron beam etc. to passtherethrough at least partially is used.

The thickness of the substrate material (1) can be suitably determinedwithout particular limitation, and is generally preferably about 10 to300 μm, more preferably 30 to 200 μm.

The pressure-sensitive adhesive used in formation of thepressure-sensitive adhesive layer (2) is not particularly limited, andis preferably a radiation-curing pressure-sensitive adhesive capable ofeasily giving a difference in adhesion between the pressure-sensitiveadhesive layers (2 a) and (2 b). The radiation-curing pressure-sensitiveadhesive can increase the degree of crosslinkage upon irradiation withradiations such as UV rays, to decrease its adhesion easily.Accordingly, the pressure-sensitive adhesive layer (2 a) havingsignificantly reduced adhesion can be easily formed by curing theradiation-curing pressure-sensitive adhesive layer corresponding to thework attachment region (3 a). Because the adhesive layer (3) or (3 a) isstuck on the pressure-sensitive adhesive layer (2 a) having reducedadhesion by curing, the interface between the pressure-sensitiveadhesive layer (2 a) and the adhesive layer (3 a) is inherently easilyseparated upon pickup. On the other hand, a region not irradiated withradiations has sufficient adhesion to form the pressure-sensitiveadhesive layer (2 b).

In the dicing die-bonding film (11) or (12), the pressure-sensitiveadhesive layer (2 b) formed by the uncured radiation-curingpressure-sensitive adhesive can adhere to the adhesive layer (3) tosecure retention upon dicing. By the radiation-curing pressure-sensitiveadhesive, the die-bonding adhesive layer (3) for fixing a chipped work(semiconductor chip etc.) to an adherend (referred to as semiconductorelement) such as a substrate and a chipped work can be retained withgood balance between adhesion and release. In the dicing die-bondingfilm (13), the pressure-sensitive adhesive layer (2 b) can fix a waferring etc.

The radiation-curing pressure-sensitive adhesive used in formation ofthe pressure-sensitive adhesive layer (2) is not particularly limitedinsofar as it has a radiation-curing functional group such ascarbon-carbon double bond and exhibits adhesiveness.

The radiation-curing pressure-sensitive adhesive can be exemplified by,for example, addition-type radiation-curing pressure-sensitive adhesiveshaving radiation-curing monomer components and oligomer componentsincorporated into general pressure-sensitive adhesives such as theacrylic pressure-sensitive adhesive, rubber-based pressure-sensitiveadhesive, silicone-based pressure-sensitive adhesive and polyvinylether-based pressure-sensitive adhesive. The pressure-sensitive adhesiveis preferably an acrylic pressure-sensitive adhesive based on an acrylicpolymer so that electronic parts such as semiconductor wafers and glasswhose pollution is undesired can be subjected to washing and cleaningwith ultra-pure water and an organic solvent such as alcohol.

The acrylic polymer includes, for example, acrylic polymers using, as amonomer component, one or more of alkyl (meth)acrylates (for example, C1to C30, particularly C4 to C18, linear or branched alkyl esters such asmethyl ester, ethyl ester, propyl ester, isopropyl ester, butyl ester,isobutyl ester, s-butyl ester, t-butyl ester, pentyl ester, isopentylester, hexyl ester, heptyl ester, octyl ester, 2-ethylhexyl ester,isooctyl ester, nonyl ester, decyl ester, isodecyl ester, undecyl ester,dodecyl ester, tridecyl ester, tetradecyl ester, hexadecyl ester,octadecyl ester, eicosyl ester etc.) and cycloalkyl (meth)acrylates (forexample, cyclopentyl ester, cyclohexyl ester etc.). The (meth)acrylatesrefer to acrylates and/or methacrylates, and the term “(meth)” in thepresent invention is all used in this meaning. From the viewpoint ofadhesion and release, the acrylic polymer preferably has a glasstransition temperature of −70° C. or more, more preferably −60° C. ormore, still more preferably −40° C. to −10° C. Accordingly, the mainmonomer forming the acrylic polymer is preferably a monomer giving ahomopolymer having a glass transition temperature of −70° C. or more.

If necessary, the acrylic polymer may contain units corresponding toother monomer components copolymerizable with the alkyl (meth)acrylateor cycloalkyl ester, for the purpose of modification of flocculation,heat resistance etc. Such monomer components include, for example,carboxyl group-containing monomers such as acrylic acid, methacrylicacid, carboxyethyl (meth)acrylate, carboxypentyl (meth)acrylate,itaconic acid, maleic acid, fumaric acid, crotonic acid etc.; acidanhydride monomers such as maleic anhydride, itaconic anhydride etc.;hydroxyl group-containing monomers such as 2-hydroxyethyl(meth)acrylate, 2-hydroxypropyl (meth)acrylate, 4-hydroxybutyl(meth)acrylate, 6-hydroxyhexyl (meth)acrylate, 8-hydroxyoctyl(meth)acrylate, 10-hydroxydecyl (meth)acrylate, 12-hydroxylauryl(meth)acrylate, (4-hydroxymethylcyclohexyl) methyl (meth)acrylate etc.;sulfonic acid group-containing monomers such as styrenesulfonic acid,allylsulfonic acid, 2-(meth)acrylamide-2-methylpropanesulfonic acid,(meth)acrylamide propanesulfonic acid, sulfopropyl (meth)acrylate,(meth)acryloyloxynapthalenesulfonic acid etc.; phosphategroup-containing monomers such as 2-hydroxyethyl acryloyl phosphateetc.; and glycidyl (meth)acrylate, (meth)acrylamide, N-hydroxymethyl(meth)acrylamide, alkyl amino alkyl (meth)acrylate (for example,dimethylaminoethyl methacrylate, t-butylaminoethyl methacrylate etc.),N-vinyl pyrrolidone, acryloyl morpholine, vinyl acetate, styrene,acrylonitrile etc. These copolymerizable monomer components can be usedalone or as a mixture of two or more thereof. The use amount of thesecopolymerizable monomers is preferably 40 wt % or less based on thewhole monomer components.

For crosslinking, the acrylic polymer can also contain multifunctionalmonomers if necessary as the copolymerizable monomer component. Suchmultifunctional monomers include hexane diol di(meth)acrylate,(poly)ethylene glycol di(meth)acrylate, (poly)propylene glycoldi(meth)acrylate, neopentyl glycol di(meth)acrylate, pentaerythritoldi(meth)acrylate, trimethylol propane tri(meth)acrylate, pentaerythritoltri(meth)acrylate, dipentaerythritol hexa(meth)acrylate, epoxy(meth)acrylate, polyester (meth)acrylate, urethane (meth)acrylate etc.These multifunctional monomers can also be used as a mixture of one ormore thereof. From the viewpoint of adhesiveness etc., the use amount ofthe multifunctional monomer is preferably 30 wt % or less based on thewhole monomer components.

The acrylic polymer is obtained by subjecting a single monomer or amixture of two or more monomers to polymerization. The polymerizationcan be carried out in any system such as solution polymerization,emulsion polymerization, bulk polymerization, suspension polymerizationetc. From the viewpoint of preventing contamination of a clean adherend,the content of a low-molecular compound is preferably lower. In thisrespect, the number-average molecular weight of the acrylic polymer ispreferably 500,000 or more, more preferably about 800,000 to 3,000,000.

To increase the number-average molecular weight of the base polymer suchas acrylic polymer etc., an external crosslinking agent can be suitablyadopted in the pressure-sensitive adhesive. The external crosslinkingmethod is specifically a reaction method that involves adding andreacting a crosslinking agent such as a polyisocyanate compound, epoxycompound, aziridine compound, melamine crosslinking agent, urea resin,anhydrous compound, polyamine, carboxyl group-containing polymer. Whenthe external crosslinking agent is used, the amount of the crosslinkingagent to be used is determined suitably depending on balance with thebase polymer to be crosslinked and applications thereof as thepressure-sensitive adhesive. Generally, the external crosslinking agentis incorporated in an amount of about 5 parts by weight or less, morepreferably 0.01 to 5 parts by weight, based on 100 parts by weight ofthe base polymer. The pressure-sensitive adhesive may be blended notonly with the components described above but also with a wide variety ofconventionally known additives such as a tackifier, aging inhibitor,filler and coloring agent if necessary.

The radiation-curing monomer component to be compounded includes, forexample, polyvalent alcohol (meth)acrylates such as trimethylol propanetri(meth)acrylate, tetramethylol methane tetra(meth)acrylate,pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate,dipentaerythritol monohydroxy penta(meth)acrylate, dipentaerythritolhexa(meth)acrylate, 1,4-butane diol di(meth)acrylate, tetraethyleneglycol di(meth)acrylate, 1,6-hexane diol (meth)acrylate, neopentylglycol di(meth)acrylate etc.; ester acrylate oligomers; andisocyanurates or isocyanurate compounds such as 2-propenyl-3-butenylcyanurate, tris(2-methacryloxyethyl) isocyanurate etc. Theradiation-curing oligomer component includes various acrylate oligomerssuch as those based on urethane, polyether, polyester, polycarbonate,polybutadiene etc., and their molecular weight is preferably in therange of about 100 to 30000.

The viscosity of the monomer components or oligomer components is notparticularly limited. The radiation-curing monomer components oroligomer components may be used alone or as a mixture of two or morethereof. Depending on the type of the pressure-sensitive adhesive layer,the amount of the components to be compounded can be suitably determinedsuch that the adhesion of the pressure-sensitive adhesive layer can bereduced. The amount of the radiation-curing monomer components andoligomer components to be compounded is not particularly limited, butfor reducing adhesion at the time of pickup, that is, after irradiationwith radiations, these components are compounded preferably in an amountof 40 to 75 wt %, more preferably 50 to 70 wt %, in the radiation-curingpressure-sensitive adhesive.

The radiation-curing pressure-sensitive adhesive includes an internalradiation-curing pressure-sensitive adhesive using a base polymer havinga carbon-carbon double bond in a polymer side chain, in a main chain orat the end of the main chain, in addition to the addition-typeradiation-curing pressure-sensitive adhesive described above. Theinternal radiation-curing pressure-sensitive adhesive does not requireincorporation of low-molecular components such as oligomer componentsetc., or does not contain such compounds in a large amount, and thus theoligomer components etc. do not move with time through thepressure-sensitive adhesive, thus preferably forming thepressure-sensitive adhesive layer having a stabilized layer structure.

As the base polymer having a carbon-carbon double bond, a polymer havinga carbon-carbon double bond and exhibiting tackiness can be used withoutparticular limitation. Such base polymer is preferably a polymer havingan acrylic polymer as a fundamental skeleton. The fundamental skeletonof the acrylic polymer includes the acrylic polymer illustrated above.

The method of introducing a carbon-carbon double bond into the acrylicpolymer is not particularly limited, and various methods can be used,and the introduction of the carbon-carbon double bond into a polymerside chain is easy in molecular design. There is, for example, a methodthat after a monomer having a functional group is copolymerized with theacrylic polymer, a compound having a carbon-carbon double bond and afunctional group capable of reacting with the above functional group issubjected to condensation or addition reaction therewith while theradiation-curing properties of the carbon-carbon double bond ismaintained.

A combination of these functional groups includes combinations ofcarboxylic acid group and epoxy group, carboxylic acid group andaziridyl group, or hydroxy group and isocyanate group. Among thesecombinations of functional groups, the combination of hydroxyl group andisocyanate group is preferable for easiness of monitoring the reaction.The functional groups may be present in either the acrylic polymer orthe above compound insofar as a combination of the functional groupsforms the acrylic polymer having a carbon-carbon double bond, and in thepreferable combination described above, it is preferable that theacrylic polymer has a hydroxyl group, and the above compound has anisocyanate group. In this case, the isocyanate compound having acarbon-carbon double bond includes, for example, methacryloylisocyanate, 2-methacryloyloxyethyl isocyanate,m-isopropenyl-α,α-dimethyl benzyl isocyanate. As the acrylic polymer,copolymers of the above-mentioned hydroxy group-containing monomer andan ether compound such as 2-hydroxyethyl vinyl ether, 4-hydroxy butylvinyl ether or diethylene glycol monovinyl ether are used.

As the internal radiation-curing pressure-sensitive adhesive, the basepolymer having a carbon-carbon double bond (particularly acrylicpolymer) can be used solely, but the radiation-curing monomer componentand the oligomer component can also be compounded to such an extent thatthe features of the pressure-sensitive adhesive are not deteriorated. Inthe case of the internal radiation-curing pressure-sensitive adhesive,the base polymer having a carbon-carbon double bond is containedpreferably in an amount of 40 wt % or more, more preferably 50 wt % ormore.

For curing with UV rays, a photopolymerization initiator is incorporatedinto the radiation-curing pressure-sensitive adhesive. Thephotopolymerization initiator includes, for example, α-ketol compoundssuch as

4-(2-hydroxyethoxy)phenyl(2-hydroxy-2-propyl)ketone,α-hydroxy-α,α′-dimethyl acetophenone, 2-methyl-2-hydroxypropiophenone,1-hydroxycyclohexyl phenyl ketone etc.; acetophenone compounds such asmethoxyacetophenone, 2,2-dimethoxy-2-phenylacetophenone,2,2-diethoxyacetophenone,2-methyl-1-[4-(methylthio)-phenyl]-2-morpholinopropane-1 etc.; benzoinether compounds such as benzoin ethyl ether, benzoin isopropyl ether,anisoin methyl ether etc.; ketal compounds such as benzyl dimethyl ketaletc.; aromatic sulfonyl chloride compounds such as 2-naphthalenesulfonyl chloride etc.; optically active oxime compounds such as1-phenone-1,1-propanedione-2-(o-ethoxycarbonyl)oxime etc.; benzophenonecompounds such as benzophenone, benzoylbenzoic acid,3,3′-dimethyl-4-methoxybenzophenone etc.; thioxanthone compounds such asthioxanthone, 2-chlorothioxanthone, 2-methyl thioxanthone, 2,4-dimethylthioxanthone, isopropyl thioxanthone, 2,4-dichlorothioxanthone,2,4-diethyl thioxanthone, 2,4-diisopropyl thioxanthone etc.; camphorquinone; halogenated ketone; acyl phosphinoxide; acyl phosphonate etc.The amount of the photopolymerization initiator to be incorporated isfor example about 0.1 to 10 parts by weight, preferably 0.5 to 5 partsby weight, based on 100 parts by weight of the base polymer such asacrylic polymer etc. constituting the pressure-sensitive adhesive.

The radiation-curing pressure-sensitive adhesive includes, for example,those disclosed in JP-A 60-196956, such as a rubber-basedpressure-sensitive adhesive and an acrylic pressure-sensitive adhesive,comprising an addition-polymerizable compound having two or moreunsaturated bonds, a photopolymerizable compound such as alkoxysilanehaving an epoxy group, and a photopolymerization initiator such as acarbonyl compound, an organic sulfur compound, a peroxide, an amine oran onium salt compound.

If necessary, the radiation-curing pressure-sensitive adhesive layer (2)can also contain a compound coloring upon irradiation with radiations.By incorporating the compound coloring upon irradiation with radiationsinto the pressure-sensitive adhesive layer (2), only a region irradiatedwith radiations can be colored. That is, the pressure-sensitive adhesivelayer (2 a) corresponding to the work attachment part (3 a) can becolored. Accordingly, whether the pressure-sensitive adhesive layer (2)was irradiated with irradiations or not can be immediately judged byvisual check, thus making the work attachment part (3 a) easilyrecognizable and facilitating attachment of a work. Further, when asemiconductor element is to be detected with an optical sensor etc., itsdetection accuracy is increased and the semiconductor element can bepicked up without error.

The compound coloring upon irradiation with radiations is a compoundthat is colorless or light-colored before irradiation with radiationsand is colored upon irradiation with radiations. Preferable examples ofsuch compounds include leuco dyes. As the leuco dyes, it is preferableto employ conventional leuco dyes based on triphenyl methane, fluoran,phenothiazine, auramine and spiropyran. Specific examples include

-   3-[N-(p-tolylamino)]-7-anilinofluoran,-   3-[N-(p-tolyl)-N-methylamino]-7-anilinofluoran,-   3-[N-(p-tolyl)-N-ethylamino]-7-anilinofluoran,-   3-diethylamino-6-methyl-7-anilinofluoran, crystal violet lactone,-   4,4′,4″-tris-dimethyl aminotriphenyl methanol, and-   4,4′,4″-tris-dimethylaminotriphenyl methane.

A developer preferably used together with these leuco dyes includeselectron acceptors such as conventionally used initial phenol formalinresin polymers, aromatic carboxylic acid derivatives, activated clayetc., and when the color tone is to be changed, a combination of variouscoloring agents can also be used.

The compound coloring upon irradiation with radiations may be dissolvedonce in an organic solvent or the like and then contained in theradiation-curing pressure-sensitive adhesive, or may be contained in afine powdery form in the pressure-sensitive adhesive. It is desired thatthe amount of this compound to be used is 10 wt % or less, preferably0.01 to 10 wt %, more preferably 0.5 to 5 wt %, based on thepressure-sensitive adhesive layer (2). When the amount of the compoundis higher than 10 wt %, the compound absorbs considerable radiationswith which the pressure-sensitive adhesive layer (2) is irradiated,resulting in insufficient curing of the pressure-sensitive adhesive (2a) thus failing to achieve sufficient reduction in adhesion in somecases. For sufficient coloration, on the other hand, the amount of thecompound is preferably 0.01 wt % or more.

The pressure-sensitive adhesive layer (2) is arranged such that theadhesion of the pressure-sensitive adhesive layer (2 a) is lower thanthe adhesion of the pressure-sensitive adhesive layer (2 b). In thedicing die-bonding film (11) or (12), the releasability of thedie-bonding adhesive layer (3) from the interface (A) is established tobe greater than the releasability thereof from the interface (B). In thedicing die-bonding film (13), the adhesion of the pressure-sensitiveadhesive layer (2 a) is established to be lower than the adhesion of thepressure-sensitive adhesive layer (2 b) where an SUS304 plate (#2000polishing) is used as the adherend.

When the pressure-sensitive adhesive layer (2) is formed from aradiation-curing pressure-sensitive adhesive, there is a method whereinthe radiation-curing pressure-sensitive adhesive layer (2) is formed onthe substrate material (1) and then cured by partially irradiating, withradiations, the region corresponding to the work attachment region (3a), to form the pressure-sensitive adhesive layer (2 a). The partialirradiation with radiations can be conducted via a photomask having aformed pattern corresponding to the region (3 b etc.) other than thework attachment region (3 a). Further, there is a method of curing byspot irradiation with UV radiations. Formation of the radiation-curingpressure-sensitive adhesive layer (2) can be carried out by transferringthe layer (2) arranged on a separator onto the substrate material (1).The radiation-curing pressure-sensitive adhesive (2) arranged on aseparator can also be subjected to curing by partial irradiation.

When the pressure-sensitive adhesive layer (2) is formed from aradiation-curing pressure-sensitive adhesive, the whole or a part of theregion other than the region corresponding to the work attachment region(3 a), on at least one side of the substrate material (1), is shieldedfrom light, and the radiation-curing pressure-sensitive adhesive layer(2) is formed on the substrate material and then irradiated withradiations to cure the region corresponding to the work attachmentregion (3 a), to form the pressure-sensitive adhesive layer (2 a) havingreduced adhesion. The light-shielding material can be formed by printingor vapor deposition of a material capable forming a photomask on asupport film. According to this production method, the dicingdie-bonding film of the present invention can be efficiently produced.

When curing inhibition occurs by oxygen upon irradiation withradiations, it is desired that the surface of the radiation-curingpressure-sensitive adhesive layer (2) be shielded from oxygen (air) by acertain method. For example, there is a method that involves coveringthe surface of the pressure-sensitive adhesive layer (2) with aseparator or a method that involves irradiation with radiations such asUV rays in a nitrogen gas atmosphere.

The thickness of the pressure-sensitive adhesive layer, similar to theconventional dicing pressure-sensitive sheet, is 1 to 50 μm. When thethickness of the pressure-sensitive adhesive layer (2) is too thick, thedicing die-bonding film upon cutting is significantly vibrated to causechipping easily, and thus the thickness is preferably 20 μm or less. Onthe other hand, when the thickness of the pressure-sensitive adhesivelayer (2) is too thin, sufficient adhesion for retaining a semiconductorelement during dicing is hardly obtained, and thus the thickness ispreferably 3 μm or more. From these viewpoints, the thickness of thepressure-sensitive adhesive layer is particularly preferably 3 to 20 μm.

When a work (semiconductor wafer etc.) contact-bonded on the die-bondingadhesive layer (3) is diced into chips, the adhesive layer (3) is alayer adhering closely to and supporting the work and simultaneouslyfunctioning as an adhesive layer for fixing a chipped work(semiconductor chip etc.) as cut fragment to a semiconductor element(substrate, chip etc.) upon mounting the chipped work. It isparticularly important that the die-bonding adhesive layer (3) hasadhesiveness by which cut fragments are not scattered during dicing ofthe work. In the dicing die-bonding film (13), the die-bonding adhesivelayer (3) is arranged as the previously formed work attachment region (3a).

The die-bonding adhesive layer (3) can be formed from a usual dieadhesive. The die adhesive is preferably the one which can be formedinto a sheet. As the die adhesive, for example, a die adhesiveconsisting of thermoplastic resin or thermosetting resin can bepreferably used. The die adhesives can be used alone or as a mixture oftwo or more thereof. The die-bonding adhesive layer is preferably theone which can stick to a work such as a semiconductor wafer or to adicing ring at a temperature of 70° C. or less. Further, the adhesivelayer is preferably the one capable of sticking at ordinarytemperatures.

The thermoplastic resin (thermoplastic die adhesive) to be used as thedie adhesive includes, for example, saturated polyester resin,thermoplastic polyurethane resin, amide resin (nylon resin), imide resinetc. The thermosetting resin (thermosetting die adhesive) includes, forexample, epoxy resin, unsaturated polyester resin, thermosetting acrylicresin, phenol resin etc. The thermosetting resin is preferablythermosetting resin which was rendered free from solvent, formed intosheet, and B-staged. A mixture of the thermosetting resin andthermoplastic resin can be used in a B-staged state. In the presentinvention, resins having a high glass transition temperature and basedon silicone, rubber, urethane, imide and acryl can also be used as thedie adhesive.

The die-bonding adhesive layer (3) may have a multilayer structure oftwo or more layers by suitably combining thermoplastic resins differentin glass transition temperature and/or thermosetting resins different inthermosetting temperature. In the step of dicing the work (semiconductorwafer etc.), cutting water is used, and thus the die-bonding adhesivelayer (3) absorbs moisture to have higher water content than undernormal conditions in some cases. When the die-bonding adhesive layercontaining water in such high content is stuck on a substrate or thelike, water vapor may be accumulated on the adhesive interface in thestage of after-curing to cause lifting. Accordingly, the die-bondingadhesive layer is constituted such that a highly moisture-permeable filmis sandwiched between the die adhesives, whereby water vapor can bediffused through the film in the stage of after-curing to prevent theproblem. Accordingly, the die-bonding adhesive layer (3) may be composedof a multilayer structure having the adhesive layer, the film and theadhesive layer laminated in this order.

The thickness of the die-bonding adhesive layer (3) is not particularlylimited, but is preferably about 5 to 100 μm, preferably about 10 to 50μm.

Thus, the dicing die-bonding film (11), (12) or (13) which has thepressure-sensitive adhesive layer (2) on the substrate material (1), andhas the die-bonding adhesive layer (3) on the pressure-sensitiveadhesive layer (2) can be obtained.

The dicing die-bonding film (11), (12) or (13) can be endowed withantistatic performance for the purpose of preventing circuits from beingbroken due to generation of static electricity upon sticking or releaseor due to charging of a work (semiconductor wafer etc.) with the staticelectricity. The antistatic performance can be conferred by a suitablesystem, for example by adding an antistatic agent or anelectroconductive material to the substrate material (1), thepressure-sensitive adhesive layer (2) or the adhesive layer (3) or byproviding the substrate material (1) with an electroconductive layerconsisting of a charge transfer complex, a metal film etc. These systemsare preferably those hardly generating impurity ions which may denaturesemiconductor wafers. The electroconductive material (electroconductivefiller) to be compounded for the purpose of conferring electricalconductivity and improving thermal conductivity includes spherical,needle-shaped or flaky metallic powder of silver, aluminum, gold,copper, nickel and electroconductive alloys, metal oxides such asalumina, amorphous carbon black, graphite etc.

In the dicing die-bonding films (1) and (2), the adhesions of the workattachment region (3 a) to the work and to the pressure-sensitiveadhesive layer (2 a) are designed preferably such that the adhesion tothe work is greater than the adhesion to the pressure-sensitive adhesivelayer (2 a). The adhesion to the work is regulated suitably depending onthe type of the work.

When the region (3 b) other than the work attachment region (3 a) isused as the dicing attachment region (3 b′) in the dicing die-bondingfilm (11), the adhesions of the dicing attachment region (3 b′) in thedie-bonding adhesive layer (3) to the work and to the pressure-sensitiveadhesive layer (2 b′) are designed preferably such that the adhesion tothe dicing ring is lower than the adhesion to the pressure-sensitiveadhesive layer (2 b′). The adhesion to the dicing ring is regulatedsuitably depending on the type of the dicing ring.

The die-bonding adhesive layer (3), (3 a) in the dicing die-bonding film(11), (12) or (13) may be protected with a separator (not shown). Thatis, the separator may be arranged arbitrarily. The separator serves as aprotecting material for protecting the die-bonding adhesive layer (3),(3 a) before use, or has a function of labeling processing or a functionof smoothing the pressure-sensitive adhesive. The separator can also beused as the substrate material for transferring the die-bonding adhesive(3), (3 a) onto the pressure-sensitive adhesive layer (2). The separatoris released when the work is stuck on the die-bonding adhesive layer(3), (3 a) in the dicing die-bonding film (11), (12) or (13).

The material constituting the separator includes paper and syntheticresin film of polyethylene, polypropylene, polyethylene terephthalate orthe like. The surface of the separator may be subjected if necessary torelease treatment such as silicone treatment, long-chain alkyltreatment, fluorine treatment etc. for improving releasability from thepressure-sensitive adhesive layer. If necessary, the adhesive sheet maybe subjected to UV protection treatment so that it does not react withenvironmental UV rays. The thickness of the separator is usually 10 to200 μm, preferably about 25 to 100 μm.

After the separator arbitrarily arranged on the adhesive layer (3), (3a) is separated if necessary, the dicing die-bonding film (11), (12) or(13) of the present invention is used in the following manner. That is,a work is contact-bonded to the die-bonding adhesive layer (3 a) in thedicing die-bonding film (11), (12) or (13), and the work is stuck andfixed to the adhesive layer (3 a). Contact-bonding is carried out in ausual manner. The sticking temperature is not limited, but is preferably20 to 80° C. In the present invention, a semiconductor wafer can be usedpreferably as the work. Then, the work is diced into chips. The workincludes, for example, a semiconductor wafer, a multilayer substrate, anintegrally-sealed module etc. In the present invention, thesemiconductor wafer can be used preferably as the work.

By dicing with a suitable means such as a rotating round blade, the worktogether with the adhesive layer (3) is cut into chipped works(semiconductor chips etc.). That is, in the dicing step, the blade isrotated at high speed to cut the work into chipped works ofpredetermined size. It is possible to employ e.g. a cutting systemcalled “full-cut” wherein cutting is carried out until thepressure-sensitive adhesive layer (2) is cut.

Then, the chipped work together with the die-bonding adhesive layer (3a) is released from the pressure-sensitive adhesive layer (2 a). Thechipped work thus picked up is then adhesive-fixed via the die-bondingadhesive layer (3 a) to a semiconductor element as the adherend. Thesemiconductor element includes a lead frame, TAB film, substrate and aseparately prepared chipped work. The adherend may be a deformableadherend which is easily deformed, or may be a non-deformable adherend(semiconductor wafer etc.) which is hardly deformed. The adherend ispreferably a semiconductor wafer. When the adhesive layer (3), (3 a) isthermally curable, the work can be stuck and fixed to the adherend bythermosetting, to improve resistance to heat. The chipped work stuck andfixed via the adhesive layer (3 a) to a substrate etc. can be subjectedto a reflow process.

Hereinafter, the present invention is described in more detail byreference to the Examples of the present invention. Hereinafter, theterm “parts” means parts by weight. For irradiation with UV rays, UVirradiation unit NEL UM-110 (manufactured by Nitto Seiki Inc.) was used.

Glass transition temperature (also referred to hereinafter as Tg) is avalue determined from Tg_(1−a) of a homopolymer of each monomer and theweight fraction W_(1−n) of each monomer, according to the equation1/Tg=W₁/Tg₁+- - - +W_(n)/Tg_(n).

Conditions for Measurement of Molecular Weight

Weight-average molecular weight was determined as “TSK standardpolystyrene” equivalent molecular weight by measurement under thefollowing conditions. GPC unit: HLC-8120GPC column manufactured byTosoh; columns, TSK gel GMH-H(S)×2 columns; size, 7.8 ml; I.D., ×300 mm;flow rate, 0.5 ml/min; detector, RI; injection volume, 100 μl; columntemperature, 40° C.; and eluent, tetrahydrofuran.

PRODUCTION EXAMPLE 1

(Substrate Material)

As the substrate material, linear low-density polyethylene of 70 μm inthickness was used. One side of this film was subjected to coronatreatment.

(Preparation of Radiation-Curing Acrylic Pressure-Sensitive Adhesive)

70 parts of butyl acrylate (Tg in homopolymer, −55° C.), 30 parts ofethyl acetate (Tg in homopolymer, −21° C.) and 5 parts of acrylic acid(Tg in homopolymer, 106° C.) were copolymerized in a usual manner inethyl acetate to give a solution of an acrylic polymer at aconcentration of 30 wt % having a weight-average molecular weight of800,000. The glass transition temperature of the acrylic polymer was−4.5° C. To this acrylic polymer solution were added 20 parts ofdipentaerythritol monohydroxy pentaacrylate, 3 parts of aphotopolymerization initiator (trade name: Irgacure 651, manufactured byCiba Specialty Chemicals Inc.), 0.5 parts of an epoxy compound (tradename: Tetrad C, manufactured by Mitsubishi Gas Chemical Company, Inc.)and 2 parts of a polyisocyanate compound (trade name: Colonate L,manufactured by Nippon Polyurethane Industry Co., Ltd.), whereby anacrylic pressure-sensitive adhesive solution was obtained.

(Preparation of Adhesive Film)

The radiation-curing acrylic pressure-sensitive adhesive solutiondescribed above was applied onto the corona-treated surface of thesubstrate material and dried at 80° C. for 10 minutes to form apressure-sensitive adhesive layer of 5 μm in thickness. Then, only awafer attachment region on the pressure-sensitive adhesive layer wasirradiated with UV rays at 500 mJ/cm² (total amount of UV rays), to givea film having the pressure-sensitive adhesive layer wherein the waferattachment corresponding region was cured with radiations. Hereinafter,this product is referred to as adhesive film A.

PRODUCTION EXAMPLE 2

(Substrate Material)

A polyethylene film of 80 μm in thickness was used as the substratematerial.

(Preparation of Radiation-Curing Acrylic Pressure-Sensitive Adhesive)

A composition consisting of 50 parts by weight of ethyl acrylate (Tg inhomopolymer, −21° C.), 50 parts of butyl acrylate (Tg in homopolymer,−55° C.) and 16 parts of 2-hydroxyethyl acrylate (Tg in homopolymer,−25° C.) were copolymerized in toluene to give a solution of an acrylicpolymer at a concentration of 30 wt % having a weight-average molecularweight of 500,000. The glass transition temperature of the acrylicpolymer was −37.5° C. This acrylic polymer solution was subjected toaddition reaction with 20 parts of 2-methacryloyloxyethyl isocyanate tointroduce a carbon-carbon double bond to a side chain of the polymermolecule. 100 parts (solids content) of this polymer was furthercompounded with 2 parts of a polyisocyanate-based crosslinking agent(trade name: Colonate L, manufactured by Nippon Polyurethane IndustryCo., Ltd.) and 3 parts of a photopolymerization initiator (trade name:Irgacure 651, manufactured by Ciba Specialty Chemicals Inc.).

(Preparation of Adhesive Film)

The radiation-curing acrylic pressure-sensitive adhesive solutiondescribed above was applied onto the above substrate material and driedat 80° C. for 10 minutes to form a pressure-sensitive adhesive layer of5 μm in thickness. Then, only a wafer attachment region on thepressure-sensitive adhesive layer was irradiated with UV rays at 500mJ/cm² (total amount of UV rays), to give a film having thepressure-sensitive adhesive layer wherein the wafer attachmentcorresponding region was cured with radiations. Hereinafter, thisproduct is referred to as adhesive film B.

PRODUCTION EXAMPLE 3

(Substrate Material)

A polyethylene film of 80 μm in thickness was used as the substratematerial.

(Preparation of Radiation-Curing Acrylic Pressure-Sensitive Adhesive)

A composition consisting of 95 parts of 2-ethylhexyl acrylate (Tg inhomopolymer, −85° C.) and 5 parts of acrylic acid (Tg in homopolymer,106° C.) was copolymerized in an ethyl acetate solution to give asolution of an acrylic polymer at a concentration of 30 wt % having aweight-average molecular weight of 700,000. The glass transitiontemperature of the acrylic polymer was −65.2° C. To this acrylic polymersolution were added 130 parts of a radiation-curing oligomer (viscosityat 25° C., 10 Pa·sec) obtained by reacting dipentaerythritol acrylatewith diisocyanate, 3 parts of a photopolymerization initiator (tradename: Irgacure 651, manufactured by Ciba Specialty Chemicals Inc.) and 5parts of a polyisocyanate compound (trade name: Colonate L, manufacturedby Nippon Polyurethane Industry Co., Ltd.), whereby an acrylicpressure-sensitive adhesive solution was obtained.

(Preparation of Adhesive Film)

The radiation-curing acrylic pressure-sensitive adhesive solutiondescribed above was applied onto the above substrate material and driedat 80° C. for 10 minutes to form a pressure-sensitive adhesive layer of5 μm in thickness. Then, a wafer attachment corresponding region on thepressure-sensitive adhesive layer only was irradiated with UV rays at500 mJ/cm² (total amount of UV rays), to give a film having thepressure-sensitive adhesive layer wherein the wafer attachmentcorresponding region was cured with radiations. Hereinafter, thisproduct is referred to as adhesive film C.

PRODUCTION EXAMPLES A TO C

(Preparation of Die-Bonding Adhesive Layers)

Each of the components consisting of the epoxy resin, phenol resin,synthetic rubber, inorganic filler and curing accelerator shown in Table1 below was compounded in the ratio shown in the same table to preparecompositions of die-bonding adhesives A to C, and each composition wasmixed with, and dissolved in, methyl ethyl ketone. The resulting mixturewas applied onto a polyester film (separator) previously subjected torelease treatment. Then, the polyester film coated with the mixture wasdried at 120° C. to remove toluene, whereby die-bonding adhesive layersA to C of 20 μm in thickness in B-stage on the polyester film wereobtained. TABLE 1 Die-bonding adhesive layer Composition A B C Epoxyresin (a1) 21 Epoxy resin (a2) 21 14.1 41.4 Phenol resin (b1) 8.1 Phenolresin (b2) 37 37.6 Synthetic rubber 20 5.6 20 Inorganic filler 72 Curingaccelerator 1 0.28 10 Tensile storage elastic 100 2000 10 modulus (MPa)

In Table 1, <Epoxy resin (a1)>Novolac epoxy resin (epoxy equivalent, 195g/eq.; softening point, 80° C.; viscosity, 0.08 Pa·s/150° C.), <Epoxyresin (a2)>Bisphenol A epoxy resin (epoxy equivalent, 185 g/eq.;viscosity, 15 Pa·s/25° C.), <Phenol resin (b1)>Phenol novolak resin(hydroxyl equivalent, 106 g/eq.; softening point, 60° C.), <Phenol resin(b2)>Phenol aralkyl resin (hydroxyl equivalent, 168 g/eq.; softeningpoint, 60° C.), <Acrylic rubber>Acrylonitrile/butadiene rubber(acrylonitrile content, 40 wt %), <Inorganic filler>Spherical silica(average particle diameter, 1 μm; maximum particle diameter, 10 μm),<Curing accelerator>Tetraphenyl phosphonium-tetra(4-methylphenyl)borate.

(Tensile Storage Elastic Modulus of the Die-Bonding Adhesive Layer)

The die-bonding adhesive layer (die-bonding film) was cut by a cutterknife into a strip of 10 mm in width, and its tensile storage elasticmodulus at 0 to 50° C. at 10 Hz frequency with a solid viscoelasticitymeasuring instrument RSAII (manufactured by Rheometric Scientific), andthe tensile storage elastic modulus at 25° C. was shown.

EXAMPLES AND COMPARATIVE EXAMPLES

The die-bonding adhesive layers A to C were attached respectively to thepressure-sensitive adhesive layers of the adhesive films A to C obtainedin Production Examples 1 to 3 at 40±3° C. to give dicing die-bondingfilms.

(Peel Adhesive Strength)

Each of the resulting dicing die-bonding films was cut into a strip of25 mm in width and stuck on the surface of a silicon mirror wafer(CZN<100>2.5-3.5 (4 inches) manufactured by Shin-Etsu Handotai Co.,Ltd.) at 40±3° C. The strip was left in a room temperature atmospherefor 30 minutes, and then the peel adhesive strength at 15° was measuredin a thermostatic chamber at 23° C. (peel point moving rate, 2.5mm/sec.). Measurement of the adhesive strength was conducted at theregion where the pressure-sensitive adhesive layer had been irradiatedwith UV rays. The results are shown in Table 2.

(Pickup Count)

A surface of a silicon mirror wafer (CZN<100> 2.5-3.5 (4 inches)manufactured by Shin-Etsu Handotai Co., Ltd.) was stuck on the regionwhere the pressure-sensitive adhesive layer of the resulting dicingdie-bonding film had been irradiated with UV rays, and subjected todicing and picked up under the following conditions to evaluate whetherpickup was feasible or not. Among 50 chipped wafers, the number ofwafers which could be picked up is shown in Table 3.

<Dicing Conditions>Dicer manufactured by DISCO; DFD-651 blademanufactured by DISCO; number of revolutions of 27HECC blade, 40000 rpm;dicing speed, 120 mm/sec.; dicing depth, 25 μm; cut mode, down cut;dicing size, 5.0 mm×5.0 mm

<Pickup Conditions>Die bonder, NEC Machinery CPS-100; number of pins;interval between 4 pins, 3.5 mm×3.5 mm; pin top curvature, 0.250 mm; pinlifting, 0.50 mm; adsorption retention time, 0.2 sec.; expansion, 3 mm.TABLE 2 15° peel adhesive strength from the die-bonding adhesive layer(N/25 mm tape width) Die-bonding adhesive layer A B C Adhesive film A0.8 1.2 13 (region cured B 0.9 1.5 31 with UV rays) C 3.1 3.7 0

TABLE 3 Pickup count (number) A B C Adhesive film A 50 50 13 (regioncured B 50 50 31 with UV rays) C 20 27 0

From Tables 2 and 3, it is recognized that the dicing die-bonding filmshaving a peel adhesive strength of not higher than 2.3 N/25 mm areexcellent in pickup properties.

The specific embodiments and examples described in the detaileddescription of the invention are intended to clarify the technicalcontent of the present invention, and not construed as limitation to thespecific examples, and can be carried out in various modificationswithin the spirit of the present invention and the scope of thefollowing patent claims.

1. A dicing die-bonding film having a pressure-sensitive adhesive layeron a substrate material and a die-bonding adhesive layer on thepressure-sensitive adhesive layer, wherein the adhesion of thepressure-sensitive adhesive layer to the die-bonding adhesive layer, asdetermined under the conditions of a peel angle of 15° and a peel pointmoving rate of 2.5 mm/sec. at 23° C., is different between a region Acorresponding to a work attachment region of the die-bonding adhesivelayer and a region B corresponding to a part or the whole of regionother than the work attachment region, of the die-bonding adhesivelayer, and satisfies the following relationship: adhesion of the regionA of the pressure-sensitive adhesive layer<adhesion of the region B ofthe pressure-sensitive adhesive layer, and the adhesion of the region Aof the pressure-sensitive adhesive layer to the die-bonding adhesivelayer is not higher than 2.3 N/25 mm.
 2. The dicing die-bonding filmaccording to claim 1, wherein the adhesions of the work attachmentregion of the die-bonding adhesive layer to the work and to the region Aof the pressure-sensitive adhesive layer satisfy the followingrelationship: adhesion to the work>adhesion to the region A of thepressure-sensitive adhesive layer.
 3. The dicing die-bonding filmaccording to claim 1, wherein a part of the region other than the workattachment region is a dicing ring attachment region.
 4. The dicingdie-bonding film according to claim 3, wherein the adhesions of thedicing ring attachment region of the die-bonding pressure-sensitiveadhesive to the dicing ring and to a part of the pressure-sensitiveadhesive layer corresponding to the dicing ring attachment regionsatisfy the following relationship: adhesion to the dicing ring<adhesionto the part of the pressure-sensitive adhesive layer.
 5. The dicingdie-bonding film according to claim 1, wherein the pressure-sensitiveadhesive layer is formed from a radiation-curing pressure-sensitiveadhesive, and the region A of the pressure-sensitive adhesive layercorresponding to the work attachment region is irradiated withradiations.
 6. The dicing die-bonding film according to claim 1, whereinthe tensile storage elastic modulus of the die-bonding adhesive layer at25° C. is 50 MPa or more.
 7. A dicing die-bonding film having apressure-sensitive adhesive layer on a substrate material and adie-bonding adhesive layer on the pressure-sensitive adhesive layer.wherein the die-bonding adhesive layer is arranged discretely as a workattachment region on a part of the pressure-sensitive adhesive layer,and the adhesion of the pressure-sensitive adhesive layer to thedie-bonding adhesive layer, as determined under the conditions of a peelangle of 15° and a peel point moving rate of 2.5 mm/sec. at 23° C., isdifferent between a region A of the pressure-sensitive adhesive layercorresponding to the work attachment region and a region B other thanthe region A, of the pressure-sensitive adhesive layer, satisfies thefollowing relationship: adhesion of the region A of thepressure-sensitive adhesive layer<adhesion of the region B of thepressure-sensitive adhesive layer, and the adhesion of the region A ofthe pressure-sensitive adhesive layer to the die-bonding adhesive layeris not higher than 2.3 N/25 mm.
 8. The dicing die-bonding film accordingto claim 7, wherein the adehsions of the work attachment region to thework and to the region A of the pressure-sensitive adhesive layersatisfy the following relationship: adhesion to the work>adhesion to theregion A of the pressure-sensitive adhesive layer.
 9. The dicingdie-bonding film according to claim 7, wherein the pressure-sensitiveadhesive layer is formed from a radiation-curing pressure-sensitiveadhesive, and the region A of the pressure-sensitive adhesive layercorresponding to the work attachment region is rradiated withradiations.
 10. The dicing die-bonding film according to claim 9,wherein the radiation-curing pressure-sensitive adhesive comprises anacrylic polymer, and its glass transition temperature is −70° C. ormore.
 11. The dicing die-bonding film according to claim 9, wherein theradiation-curing pressure-sensitive adhesive comprises an acrylicpolymer, and its weight-average molecular weight is 500,000 or more. 12.The dicing die-bonding film according to claim 11, wherein the tensilestorage elastic modulus of the die-bonding adhesive layer at 25° C. is50 MPa or more.
 13. A method of fixing a chipped work using the dicingdie-bonding film of claim 1, which comprises: contact-bonding a workonto the die-bonding adhesive layer at the work attachment region,dicing the work into a chipped work, releasing the chipped work togetherwith the die-bonding adhesive layer from the pressure-sensitive adhesivelayer, and adhesive-fixing the chipped work via the die-bonding adhesivelayer onto a semiconductor element.
 14. The fixing method according toclaim 13, wherein the thickness of the work is less than 100 μm.
 15. Amethod of fixing a chipped work using the dicing die-bonding film ofclaim 7, which comprises: contact-bonding a work onto the die-bondingadhesive layer, dicing the work into a chipped work, releasing thechipped work together with the die-bonding adhesive layer from thepressure-sensitive adhesive layer, and adhesive-fixing the chipped workvia the die-bonding adhesive layer onto a semiconductor element.
 16. Thefixing method according to claim 15, wherein the thickness of the workis less than 100 μm.
 17. A semiconductor device comprising a chippedwork adhesive-fixed via a die-bonding adhesive onto a semiconductorelement by the method of fixing a chipped work according to claim 13.18. A semiconductor device comprising a chipped work adhesive-fixed viaa die-bonding adhesive onto a semiconductor element by the method offixing a chipped work according to claim 15.